Systems and methods for coupling and decoupling a catheter

ABSTRACT

A convertible nephroureteral catheter is used in the treatment of urinary system complications, particularly on the need for a single surgically delivered device to treat patients who must be seen by an interventional radiologist (IR). In many current procedures, patients need to return to the operating room to remove a previously delivered nephroureteral catheter to exchange this catheter with a fully implanted ureteral stent delivered though the same access site at the flank. The present convertible nephroureteral catheter reduces the need to return for a second surgical procedure. Two weeks after initial implantation, the proximal portion of the convertible nephroureteral catheter extending out from the body may simply be removed. A simple action at the catheter hub allows this proximal portion to be removed, leaving behind the implanted ureteral stent within the patient&#39;s urinary system. Other medical procedures, devices, and technologies may benefit from the described convertible catheter.

CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Application No.62/036,377, filed Aug. 12, 2014, which application is incorporatedherein by reference.

The subject matter of this application is related to the subject matterof U.S. patent application Ser. No. 12/559,946, filed Sep. 15, 2009 andnow issued as U.S. Pat. No. 8,657,884, and Ser. No. 14/159,221, filedJan. 20, 2014, which applications are incorporated herein by reference.

BACKGROUND

The ureteral stent is a medical device used within a patient populationwhich experience one or more complications associated with the urinarysystem which includes the kidneys, ureters and bladder. A host ofcomplications may affect urinary flow and how these organs handle thisfunction; these complications ranging from decreased urine flow toswelling of the kidneys or bladder, with many of these conditions beingadversely impacted by the formation of kidney stones. To alleviateurinary system complications, a device or device(s) are placed eitherwithin the bladder, one or both of the kidneys, and/or one or both ofthe patient's ureters. The devices used in these areas are known asnephrostomy catheters (delivered percutaneously within a kidneycollecting system), nephroureteral catheters (delivered percutaneouslyand extending distally into the bladder), urinary catheters (deliveredthrough the urethra), or ureteral stents (delivered percutaneously orthrough the urethra).

The focus of the present disclosure will surround the delivery methodand use of the nephroureteral catheter and the ureteral stent, which areoften used one after the other in percutaneous cases to deal with apatient's urinary system complications. Once a patient has exhibitedurinary complications and a ureteral stent implantation is recommended,a urologically delivered stent placement will often be attempted. Insome cases, this cannot be achieved by the urologist due to a variety ofpossible factors, resulting in the patient being sent to theinterventional radiologist (IR). The IR may then attempts to deliver anephroureteral stent percutaneously though the backside of the patientand into the impacted kidney, with said device extending distally intothe bladder. The proximal end of the nephroureteral catheter therebyremains outside of the patient for up 2 weeks, giving the access sitesufficient time to heal before removal. Once the access site has fullyhealed the patient is typically sent back to the operating room for asecond interventional procedure whereby the nephroureteral stent isremoved and a ureteral stent is then delivered. This ureteral stentdiffers from the nephroureteral stent in that its proximal tipterminates within the kidney's renal pelvis. This ureteral stent has acurl at its distal end which resides in the bladder and a proximal curlwhich resides in the renal pelvis. This device may reside in the patientfor up to 6 months or in some cases longer and may be removedurologically. This two-step approach and the devices used may be lessthan ideal in many cases. There are needs to overcome at least some oftheir drawbacks.

SUMMARY

According to many embodiments, integrating the functionalities of twoexisting devices used for the percutaneous treatment of urinarycomplications into a single device has been devised, with particularfocus on the methods, designs and materials which may be utilized tocouple these two devices together in a fashion which allows a decouplingat a later time state. Many embodiments provide a single device whichmay combine the functionalities of a nephroureteral catheter andureteral stent, but can maintain the ability to perform the full removalof the proximal (catheter) portion of the device extending out of thepatient's body during the early stages of implantation (up to 2 weeks).

The decoupling (release) mechanism can allow the proximal portion ofthis combination device to be removed without the need for a secondinterventional procedure. The primary modes of function of this couplingmechanism include, but are not limited to, the following: (1) tomaintain connection of proximal (catheter) portion of device to distal(stent) portion of device, and (2) to permit the removal of the proximalportion of device at a later time leaving behind distal portion ofdevice within the patient's urinary collecting system. The decouplingnature of the proximal portion of the device may be achieved byproviding an input to the proximal hub of the device which extends outof the patient's body. This input to decouple catheter from stent may beperformed by the push of a button, the rotation of a luer, the insertionof a tool, the removal of a wire or a series of similar events alloccurring at the proximal hub, or the like. Additionally, independent ofthe coupling mechanism, a strand of material, typically with a circularcross-section, can be used to assist in the closure of the stent'sproximal loop once the device has been delivered into the patient. Thisis often necessary due to the tighter space the renal pelvis providesfor this proximal loop to reside. This strand of material may be calledthe ‘proximal loop suture’ and may pass through side holes cut into thestent allowing for proximal loop closure. This ‘proximal loop suture’may be fully removed from the device without inhibiting thefunctionality of the coupling interface between the proximal and distalportions of the device.

Several depictions of the coupling interface between the catheter andstent are shown in the Figures. This coupling interface would permit theutilization of a single surgical procedure as opposed to two, puttingthe patient at significantly less risk for complications in theoperating room environment. The decoupling may be achieved by an inputto the proximal hub performed at bedside or by the insertion of adecoupling tool, thereby removing catheter portion of device once deemednecessary. A coupled device may be achieved in many ways as describedherein. An example of a coupling may include an expandable inner memberwhich retains the distal member with the proximal member by expandingwithin the stent lumen to couple and once an input is applied toproximal hub, said expanded element may collapse and decouple thedevice. Some of the depictions below may provide a safe and effectiveways to combine the nephroureteral catheter and the ureteral stent whilestill providing the utility of separate devices and two surgicalprocedures.

Aspects of the present disclosure provide surgically delivered medicaldevices. An exemplary medical device may comprise a proximal portionwhich extends outside of a patient's surgical access site. The proximalportion of device may be removed at a later date, converting the distalportion of device into an implant. The device may comprise a distal(stent) member and a proximal (catheter) member. The proximal and distalmembers may be coupled to one another in a concentric fashion via aninner member extending out from the proximal member. The proximal anddistal members may be coupled in one of or a combination of manyembodiments.

In many embodiments, the device may employ suture loop lock(s) to couplethe proximal member to the distal member. The suture loop lock(s) maywrap around one or more pull wire(s) at the inner member to stentinterface. Furthermore, suture tail(s) may extend proximally to the hubof device and may be locked into place with tension applied to achieveleveraged coupled interface.

In many embodiments, the device may employ suture loop lock(s) whichwrap around the inner member at the stent interface region to achievecoupling of proximal and distal members. Furthermore, suture tail(s) mayextend proximally to hub of device and may lock into place with tensionapplied to achieve leveraged coupled interface.

In many embodiments, the device may comprise an inner member which isfixed at the distal region of proximal catheter. The inner member maycontain a smaller tube affixed within its lumen. The smaller tube may beused as a receiver for a ball wire, which may extend from distal member,and a pull wire, which may extend from proximal member. Once the ballwire has passed through the smaller tube, the pull wire may be passedthrough which may prevent passing of ball until pull wire is removedfrom device.

In many embodiments, the device may comprise an inner member which isfixed at the distal region of the proximal catheter. The inner membermay include a superelastic/shape memory element which may be used as areceiver described above.

In many embodiments, the proximal and distal members of the device maybe coupled to one another using a ring locking style mechanism, with onering element affixed to distal member and another ring element affixedto proximal member. The ring members may be held coincident using aninner member and a pull wire.

In many embodiments, the device may comprise a keyed locking system,such as mating hexagonal elements, with one hex element affixed toproximal member and another hex element affixed to distal member toachieve coupling. The hex elements may be engaged or disengaged using acounter rotating tool.

In many embodiments, the inner member may extend fully from proximal hubto achieve concentric junction between the distal and proximal members.In addition, the inner member may be fixed or movable at hub and alongentire catheter length.

In many embodiments, the inner member may be a component which isaffixed to the distal or proximal member and only extends for afractional portion of the device's length.

In many embodiments, the inner member may be formed as a necking of thedistal region of the catheter itself which is then inserted into thelumen of the distal (stent) member.

In many embodiments, the proximal and distal members of the device maybe coupled to one another through the employment of an adhesive layer onthe inner member region which extends into the distal member.

In many embodiments, the proximal and distal members of the device maybe coupled to one another through the employment of an oversizeddiameter of the inner member resulting in a frictional fit with thestent.

In many embodiments, the proximal and distal members of the device maybe coupled to one another through the employment of a metallic orpolymeric crimp which may be applied to the outside of the stent whichoverlaps the inner member extending into its lumen.

In many embodiments, the proximal and distal members of the device maybe coupled to one another through the employment of a superelastic/shapememory alloy affixed to the distal member which may interface withprotrusions on the outer surface of the inner member. Thereby, the innermember may not be movable until the catheter or peel-away sheath hasbeen removed and shape memory alloy mechanism releases inner member.

In many embodiments, the proximal and distal members of the device maybe coupled to one another through the use of a mechanically modifiedsurface of the inner member which, once inserted into distal member, aninterfacing region of the distal member may be heated and a polymer maybe allowed to flow into the mechanical alterations of inner member. Thepolymer may furthermore be allowed to cool, forming a permanentmechanical interface between the two elements until the inner member ispulled away from distal member using a light to moderate pull force.

In many embodiments, the proximal and distal members of the device maybe coupled to one another through the use of a female to male threadstyle arrangement at the coupling interface.

In many embodiments, the proximal and distal members of the device maybe coupled to one another using electrically releasable metallicelement(s), which may couple the proximal and distal members until atool can be used to electrically disengage said elements.

In many embodiments, the proximal and distal members of the device maybe coupled to one another using magnets affixed to proximal and distalmembers and may be disengaged by pulling proximal member away fromdistal member or by rotating one or both of magnetic components withinsaid members using a tool or other components incorporated withindevice.

In many embodiments, the proximal and distal members of the device intheir coupled state may be disengaged using a separate tool which maydecouple proximal and distal members by an input of rotation, electricalstimulus or ultrasonic vibration.

Aspects of the present disclosure also provide further stent deliverysystems. An exemplary stent delivery system may comprise a catheterbody, a stent member, an inner member, and a tether. The catheter bodymay have an inner lumen and a proximal end and a distal end. The stentmember may have an inner lumen and a proximal end releasably coupledwith the distal end of the catheter body. The inner member assembly maybe disposed in the inner lumen of the catheter body and may extend intothe inner lumen of the stent member to concentrically align the catheterbody and the stent member. The tether may extend through or along thecatheter body and into the inner lumen of the stent member to form aloop over at least a portion of the inner member assembly, therebysecuring the stent member to the catheter body. Retraction of the innermember from the inner lumen of the stent member may free the innermember assembly from the loop such that the stent member is releasedfrom the stent body.

The inner member assembly may comprise a locking pull wire. The lockingpull wire may be threadable through the loop of the tether. The innermember assembly may comprise a hypotube. The inner member assembly maybe configured to be actuated with one or more pull tabs or rotatablecaps at a hub coupled to the proximal end of the catheter body.

The tether may extend through the inner lumen of the catheter body. Thetether may extend out of a lateral port of the catheter body near thedistal end of the catheter body. The loop formed by the tether mayextend into stent member through a lateral port of the stent member tobe threaded through by the at least a portion of the inner memberassembly within the inner lumen of the stent member. The tether may havea fixed end near the distal end of the catheter body and a free end. Thetether may extend proximally toward the free end and the proximal end ofthe catheter body. The tether may have a first end and a second end. Thetether may extend proximally toward both the first and second ends andthe proximal end of the catheter body.

The stent member may comprise a proximal loop and a distal loop. One ormore of the proximal loop or the distal loop of the stent member mayhave a straightened configuration and a looped configuration. One ormore of the proximal loop or the distal loop may be biased to assume thelooped configuration. The stent delivery system may further comprise aloop pull wire extending through the inner lumen of the catheter bodyand coupled to the proximal loop. Retracting the loop pull wire may pullthe proximal loop into the loop configuration or may lower a radius ofthe proximal loop. The loop pull wire may extends out from a firstlateral port of the stent member near the proximal end of the stentmember and may extend back into a second lateral port of the stentmember near a distal end of the proximal loop. The loop pull wire may beretractable from a pull tab or rotatable cap at a hub coupled to theproximal end of the catheter body.

Other exemplary stent delivery systems may comprise a catheter body, acatheter member, and an inner member assembly. The catheter body mayhave an inner lumen and a proximal end and a distal end. The cathetermember may have an inner lumen and a proximal end which is fixed orreleasably coupled with a stent element extending from within the lumenof the proximal end of the stent body. The inner member assembly may bedisposed in the inner lumen of the catheter body and may extend into theinner lumen of the stent member to concentrically align the catheterbody and the stent member.

In some embodiments, the stent delivery system further comprises a wireextending through or along the entire or a portion of the catheter bodyand into the inner lumen of the stent body to interface the cathetermember, with the stent element thereby securing the stent body to thecatheter body. Retraction of the wire from the inner lumen of thecatheter member may free the inner member assembly from the stentelement such that the catheter member is released from the stent body.

In some embodiments, the stent delivery system may further comprise awire extending through or along the entire or a portion of the catheterbody and into the inner lumen of the stent member, subsequentlyinterfacing with the superelastic assembly in a releasable fashion tosecure the stent member to the catheter body. Retraction of the wirefrom the inner lumen of the stent member may free the superelastic innermember assembly from such that the stent member is released from thestent body.

In some embodiments, the stent delivery system may further comprise atether extending through or along the catheter body and into the innerlumen of the stent member to form a loop over at least a portion of theinner member assembly, thereby securing the stent member to the catheterbody. Retraction of the inner member from the inner lumen of the stentmember may free the inner member assembly from the loop such that thestent member is released from the stent body.

In some embodiments, the stent delivery system may further comprise atether extending through or along the catheter body and into the innerlumen of the stent member to form a loop over at least a portion of theinner member assembly, thereby securing the stent member to the catheterbody. Retraction of the inner member from the inner lumen of the stentmember may free the inner member assembly from the loop such that thestent member is released from the stent body.

In some embodiments, the stent delivery system may further comprise anadhesive which is applied to the inner lumen of the stent member toaffix the inner member assembly to the stent member extending through oralong the catheter body and into the inner lumen of the stent member,thereby securing the stent member to the catheter body. Retraction ofthe inner member at a threshold load may allow a break away from thebonded surface of the stent member such that the inner member isreleased from the stent body.

In some embodiments, the stent delivery system may further comprise africtional interference between the inner member and the stent member.The frictional interference may be applied to the inner lumen of thestent member to affix the inner member assembly to the stent memberextending through or along the catheter body and into the inner lumen ofthe stent member, thereby securing the stent member to the catheterbody. Retraction of the inner member at a threshold load may allow abreakaway of the frictional interference with the stent member such thatthe inner member is released from the stent body.

In some embodiments, the stent delivery system may further comprise ametallic crimp or swaged band element. The metallic crimp or swaged bandelement may be applied over the outside of the stent body toward itsdistal end to affix the inner member assembly to the stent memberextending through or along the catheter body and into the inner lumen ofthe stent member thereby securing the stent member to the catheter body.Retraction of the inner member at a threshold load may allow a breakawayfrom the frictional interference resulting from the crimp element suchthat the inner member is released from the stent body.

In some embodiments, the stent delivery system may further comprise asuperelastic mechanism extending from the stent body. The superelasticmechanism may interface with the inner member in a locked state untilthe catheter body is removed, at which point the superelastic mechanismmay release the inner member from its locked state allowing its completeremoval.

In some embodiments, the stent delivery system may further comprise athermoforming process applied to the inner member allowing it tointerface with the stent member to affix the inner member assembly tothe stent member extending through or along the catheter body and intothe inner lumen of the stent member, thereby securing the stent memberto the catheter body. Retraction of the inner member at a threshold loadmay allow a breakaway from the thermoformed surface of the stent membersuch that the inner member is released from the stent body.

In some embodiments, an inner member and stent member may interface andlock together via threaded surfaces to affix the inner member assemblyto the stent member extending through or along the catheter body andinto the inner lumen of the stent member, thereby securing the stentmember to the catheter body. Rotation of the inner member out from thestent member may enable inner member to be released from the stent body.

The stent delivery systems may further be configured in any number ofways described above and herein.

Aspects of the present disclosure also provide methods for deliveringnephroureteral or other stents. A stent delivery system may be advancedthrough a percutaneous access site so that a distal end of a stentmember of the stent delivery system is positioned in a bladder and aproximal end of the stent member is positioned in a renal pelvis. Thedistal end of the stent member may form a distal loop in the bladder.The proximal end of stent member may be actuated to form a proximal loopin the renal pelvis. The stent member may be decoupled from a catheterbody of the stent delivery system. The catheter body of the stentdelivery system may be retracted from the percutaneous access site,leaving the stent member in place.

To actuate the proximal end of the stent member to form a proximal loopin the renal pelvis, a loop pull wire extending through the catheterbody may be retracted to reduce a radius of the proximal end of thestent member.

To decouple the stent member from the catheter body, a lock pull wiremay be retracted from the stent member to free a tether loop extendinginto the stent member from the catheter body and/or an inner member maybe retracted from the stent member. The inner member may be configuredto concentrically align the catheter body with the stent member whenadvanced therethrough.

The member and the catheter body of the stent delivery system may beleft in place for at least 3 days before the stent member is decoupledfrom the catheter body and the catheter body is retracted from thepercutaneous access site. In some embodiments, urine is be drainedthrough the catheter body of the stent left in place. In someembodiments, the catheter body of the stent left in place is capped.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the present disclosure are set forth withparticularity in the appended claims. A better understanding of thefeatures and advantages of the present disclosure will be obtained byreference to the following detailed description that sets forthillustrative embodiments, in which the principles of the presentdisclosure are utilized, and the accompanying drawings which displayvarious embodiments of the coupling mechanism to be used in thefabrication of the convertible nephroureteral catheter and are describedas follows.

FIG. 1 is a side view of an example convertible nephroureteral catheter,according to many embodiments.

FIG. 2 is a side section view detailing two coupling methods utilizingthe principle of a suture loop lock in conjunction with a pull wire,according to many embodiments.

FIGS. 3A and 3B are side section views of a suture loop lock similar tothat of the previous figures, but where the inner member of the catheteris grabbed by the suture loop(s) as opposed to using a pull wire,according to many embodiments.

FIGS. 4A, 4B, 4C, and 4D are side section views of the coupling regionbetween the catheter (proximal member) and stent (distal member) withelements that have been affixed to both proximal and distal memberswhich may be used for coupling and decoupling of said members (withdecoupling means achieved by removing pull wire from assembledelements), according to many embodiments.

FIGS. 5A and 5B are perspective and side section views, respectively, ofthe coupling region which may utilize a superelastic/shape memory alloyaffixed to proximal and/or distal member, according to many embodiments.

FIGS. 6A, 6B, and 6C are perspective views of a coupling region whichutilizes locking ring elements to join proximal and distal members; and,FIG. 6D is a side section view of this coupling region.

FIG. 7A is a side view of a coupling region which utilizes hexagonalelements affixed to proximal and distal members to achieve coupling;FIG. 7B shows a front section view of the coupling region; FIG. 7C showsa side view of the coupling region; FIG. 7D shows a perspective view ofthe coupling region; FIG. 7E shows a tool that may be used to actuatethe hexagonal elements in the coupling region; and FIG. 7F shows ahandle mechanism for the tool, according to many embodiments.

FIGS. 8A, 8B, and 8C shows side views of coupling configurations,according to many embodiments.

FIG. 9 shows a side section view of the application of an adhesive oninner member of catheter to achieve coupling between proximal and distalmembers, according to many embodiments.

FIG. 10 shows a side section view of a friction/press fitting of theinner member of the catheter into the lumen of the stent to achievecoupling of proximal and distal members, according to many embodiments.

FIGS. 11A and 11B show side views of a metallic element applied to theouter surface of the stent to crimp a catheter inner member to achievecoupled state, according to many embodiments.

FIGS. 12A and 12B show side views of the use of a superelastic/shapememory alloy affixed to stent used to couple proximal and distalmembers, according to many embodiments.

FIGS. 13A and 13B show side views of a method to couple proximal anddistal members by thermally processing a region of stent, according tomany embodiments.

FIG. 14 shows a side section view detailing a threaded coupling wherebydistal member (stent) has female threads (inner surface) and proximalmember (catheter) has male threads over its outer surface within thecoupling region, according to many embodiments.

FIGS. 15A, 15B, and 15C show side views displaying the proximal loopsuture and its independent functionality from the coupling mechanism,according to many embodiments.

FIGS. 16A, 16B, and 16C show side views detailing several proximal hubconfigurations, according to many embodiments.

FIG. 17A shows a side view of a nephroureteral stent system, accordingto many embodiments.

FIG. 17B show a side view of the nephroureteral stent system of FIG. 17Awith the stent member detached.

FIG. 17C shows a side section view of the coupling and release mechanismof the nephroureteral stent system of FIG. 17A.

FIG. 17D shows a perspective view of the lock/release wire of thecoupling and release mechanism of FIG. 17C.

FIG. 17E shows a side view of the nephroureteral stent system of FIG.17A.

FIG. 17F shows a magnified view of the proximal loop of the stent memberof the nephroureteral stent system of FIG. 17A.

FIGS. 18A, 18B, and 18C show side section views of a coupling andrelease mechanism releasing the stent member of a nephroureteral stentsystem, according to many embodiments.

FIG. 19 shows a side section view of a side section view of a couplingand release mechanism for a nephroureteral stent system, according tomany embodiments.

FIG. 20 shows a side section view of a side section view of a couplingand release mechanism for a nephroureteral stent system, according tomany embodiments.

FIG. 21 shows a side section view of a side section view of a couplingand release mechanism for a nephroureteral stent system, according tomany embodiments.

FIGS. 22A and 22B show perspective and perspective side section views ofan exemplary hub for a nephroureteral stent system, according to manyembodiments.

FIGS. 23A-23D show another exemplary hub for a nephroureteral stentsystem, according to many embodiments. FIGS. 23A, 23B, and 23C showperspective views of the hub. FIG. 23A shows the hub being axiallycollapsed, FIG. 23B shows the hub being partially separated, and FIG.23C shows the hub being fully separated out so that multiple pull tabscan be used. FIG. 23D shows a side section view of the hub.

FIG. 24 shows further exemplary hubs for nephroureteral stent systems,according to many embodiments.

FIG. 25A show perspective views of various rotating hemostat type valvesusable for various convertible stent systems, according to manyembodiments.

FIG. 25B shows a perspective view of a center lever lock usable forvarious convertible stent systems, according to many embodiments.

FIG. 26 shows a section view of a convertible stent system showing thearrangement of its loop suture, according to many embodiments.

DETAILED DESCRIPTION

FIG. 1 provides a perspective of an example configuration of theconvertible nephroureteral catheter 100. FIG. 2 details the couplingregion of proximal member (catheter) 110 and distal member (stent) 120with two example configurations shown. The release mechanism shown maycomprise two elongated members—suture 130 and pull wire 140. As shown inFIG. 2, the suture 130 may exit through the wall of the proximal member110 and reenter the distal member 120, holding the proximal and distalmembers 110, 120 together across the junction 150. The pull wire 150 cankeep the suture 140 from pulling out until the pull wire (lock wire) 150is removed or proximally retracted. The distal portion of the suture 140may form a loop through which the distal portion of the pull wire 150 isthreaded through. Additionally, an inner-member 160 may be included tocross the junction 150 on the inside to keep junction aligned(concentric) and facilitate passage of other components across thejunction 150. Various configurations are shown in FIG. 2, where thesuture 130 can be inside the inner member 160 and pass through the innermember 160 in addition to proximal and distal members 110, 120(Configuration 2A). Alternatively or in combination, the suture 130 canbe outside the inner member 160 and pass through only the proximal anddistal members 110, 120 (Configuration 2B). Both the pull wire 140 andthe suture 130 may be made of various suitable materials and shapes ofmaterials, as well as other components. To release the locking suture130, the pull wire 140 may be pulled proximally from a pull tab 170 onthe handle portion or proximal hub 100 a of the convertible catheter100. FIGS. 3A and 3B detail an additional configuration of the sutureloop 130 lock(s) which may wrap around inner member 160 as opposed toutilizing a pull wire 140 to achieve coupling. The distal portion of thesuture 140 may form a loop through which the distal portion of the innermember 160 is threaded through (FIG. 3A). When the inner member 160 isretracted proximally, the distal loops of the suture 140 may be releasedwhich allows the proximal and distal members 110, 120 to separate. Insome embodiments, the inner member 160, the proximal member 110, and thedistal member 120 may form an interference fit with one another at thejunction 150 to prevent displacement of the proximal and distal members110, 120, although this interference fit may be decoupled by retractionof the inner member 160 relative to the junction 150. In someembodiments, the distal member 120 may comprise stops 125 along theinner surface of its lumen to restrict the distal advancement of theinner member 160 into the lumen (FIG. 3B).

FIGS. 4A-4D display enhanced perspectives of the coupling region betweendistal (stent) members 110 and proximal (catheter) members 120 of thedevice 100. Various elements which may be fabricated from metallic orpolymeric materials, may be affixed to the coupling region of theproximal member 120. Shown by FIGS. 4A-4D is a large diameter tubesegment 401 and joined to inner surface of said element 401 may be asmall tube element 402. On the distal member 120, a marker band 406 maybe applied, with a ball wire 403 extending proximally from marker band406 and terminating at junction 404 (FIGS. 4A, 4B). The ball wire 403may be passed through the small tube element 402 with the diameter ofthe ball wire 402 being slightly smaller than the inner diameter of thesmall tube element 402. Once the ball portion of ball wire 403 has fullypassed through small tube element 402, a pull wire 405 can then bepassed through small tube element 402 as in FIGS. 4C and 4D. Theadditive diameter of the pull wire 405 and the diameter of the ball wire403, but not the ball itself, may not be greater than the inner diameterof the small tube element 402. The ball wire's 403 ball diameter plusthe pull wire 405 diameter may exceed the inner diameter of the smalltube 402, coupling the distal and proximal members 110, 120 until thepull wire 405 is removed. This pull wire 405 may be affixed to a regionon the proximal hub 110 a, allowing for removal by pulling it out of thedevice 100.

FIGS. 5A and 5B display proximal member 110 which may function in asimilar fashion to the corresponding member 110 shown in FIGS. 4A-4D.The proximal member 110 may include a superelastic/shape memory elementor tab 501 used to receive ball wire and pull wire components. Thissuperelastic/shape memory element or tab 501 may function in a similarfashion to the small tube segment or element 402 shown in FIGS. 4A-4D.The tab 501 may replace the small tube segment or element 402 and thetab 501 may be integral to the proximal member 110. The tab 501 shown onthe proximal member 110 may be heat set into a downward or upwardsposition to couple the distal member 120 and the superelastic propertiesof the tab 501 may enable it to relocate as an input is induced to theproximal hub 110 a or interior lumen so as to allow a decoupling tooccur. This tab 501, along with all other inner member components, maybe situated anywhere along the entire length of the proximal member 110.

FIGS. 6A-6D show perspective views of the coupling region or junction150 which utilizes locking ring elements 601 to join proximal and distalmembers 110, 120, which may be held coincident using a pull wire 606.FIG. 6A shows the proximal and distal members 110, 120 with locking ringelements 601 and FIG. 6B shows the same with the pull wire 606 threadedthrough the holes or apertures of the locking ring elements 601 to holdthe proximal and distal members 110, 120 together. FIGS. 6C and 6D showlocking ring elements 110 a, 120 b which may extend out from theinterfacing ends of proximal and distal members 110, 120 at the junction150. The two ring members 110 a, 120 a can be screwed (e.g., the ringmembers may have a high pitch such as a ¼ turn) and a wire 606 a maylock the two ring members 110 a, 120 a in place. The two ring members110 a, 120 a may be easily un-coupled once the wire 606 a is removed.The locking ring elements 110 a, 120 a may have apertures or holesthrough which the pull wire 606 a is threaded through.

FIGS. 7A-7D show views of the coupling region or junction 150 whichutilizes keyed (hexagonal shape shown to illustrate) elements affixed toproximal and distal members 110, 120 to achieve coupling. The innermember assembly coupling the stent to the catheter may bethreaded/rotationally interlocked (like a ¼ turn or other thread) andkeyed (e.g., hexed). As shown in FIG. 7A, one of the proximal or distalmembers 110, 120 may be held stationary while the other is turned todecouple the proximal and distal members 110, 120. A tool with coaxialmembers may be provided. The tool may hold one of the proximal or distalmembers 110, 120 stationary and can rotate the other to unscrew them.The tool may put down the catheter/proximal member 110 (i.e., advancedwithin the lumen of the catheter) to engage the inner member assembly atthe time of disconnect. The stent/distal member 120 may be held steadyand the part affixing the stent/distal member 120 to thecatheter/proximal member 110 may be unscrewed. The catheter/proximalmember 110 may be twisted while the stent/distal member 120 isdecoupled. A pull wire may not be necessary with use of the tool toassist decoupling. FIG. 7B shows a side section view of the junction150, showing a first keyed portion 701 a coupled to the second keyedportion 701 b. FIG. 7C shows a side view of the junction 150, showingthe first keyed portion 701 a in alignment with the second keyed portion701 b. FIG. 7D shows a perspective section view of the same. Whilehexagonal shapes for the keyed portions are shown, other shapes such asstar or torx like shapes may be used instead. The present disclosurealso provides a counter rotating tool 751 to engage and unlock proximaland distal portions 110, 120, without twisting the distal portion 120(FIGS. 7E, 7F). The handle mechanism of the tool may allowed the keyedshape to be rotated while the outer bodies of the proximal and/or distalportions 110, 120 are held stationary.

FIGS. 8A to 8B show side section views of the coupling region 150 inwhich the use of the inner member 160 of the catheter 100 is utilized inseparate configurations to maintain concentricity between stent member120 and catheter member 110. A variety of coupling mechanisms may beused with any of these inner member 160 configuration styles. FIG. 8Ashows a configuration in which the functionality of the inner member 110has been formed onto the distal tip of the catheter member 110. Thisdistal tip of the catheter member 110 may slide into the lumen of thestent member 120. FIG. 8B shows a configuration whereby the inner member160 does not extend back to the proximal hub 100 a; this inner member160 may be a component which is affixed to the catheter member 110 ofthe device 100 similar to the design style shown in FIGS. 4A-4D. FIG. 8Cdisplays a configuration in which the inner member 160 extending fullyback to the proximal hub 100 a and being fixed into place at the hubregion. The catheter distal tip may be formed to taper in toward theinside lumen of stent, it may utilize a fixed inner member at thecatheter's distal end, or it may be a slidable component which may befully removed from the catheter lumen.

FIG. 9 shows the use of an adhesive may be applied to the region of theinner member 160 region 160 a which is in contact with the lumen of thestent member 110. This adhesive joint may effectively couple the innermember 160 and its corresponding outer catheter member 110 to the stentmember 120 (outer catheter member 110 not shown in FIG. 9 or 10).

FIG. 10 shows the use of an interference fit where the inner member 160has an oversized diameter, which when passed into the lumen of the stentmember 120, a frictional fitting joint is achieved.

FIGS. 11A and 11B show the use of a metallic or polymeric crimp 1101applied to the outside of the stent member 120, circumferentiallycollapsing that region over the inner member 160 of the catheter member110 resulting in a coupled region.

FIGS. 12A and 12B show the use of a superelastic/shape memory alloywhich in this case has been affixed to the stent member 120 which mayinterface with protrusions 1206 affixed to the inner member 160 of thecatheter 100. The stent member 120 may comprise a peel-away sheath 1201acting as the catheter tube (FIG. 12A), whereby the peel away sheath1201 would be the first element of the device 100 to be removedresulting in the release (shape alloy memory effect) of the wiresgrabbing protrusions 1206 on the outer surface of the inner member 160from a super elastic component 1211 of the stent member 120, thusallowing for the complete removal of the inner member 160 thereafter.

FIGS. 13A and 13B show where the region of the stent member 120 thatinterfaces with the inner member 160 is thermally processed. FIG. 13Ashows the coupling region or junction 150 before processing and FIG. 13Bshows the coupling region or junction 150 after processing. The innermember 160 may have a series of grooves 160 a cut circumferentiallyabout its surface, these grooves 160 a serving as a region with whichthe polymer material of the stent member 120 may flow into when saidregion is heated. Once the stent member polymer is heated and has joinedto the inner member 160, it is then allowed to cool permanently forminga mechanical interface between the two elements. A light to moderatepull force applied to the inner member 160 would allow it to break awayfrom the stent member 120.

FIG. 14 details a coupling configuration which permits the distal member(stent) 120 to receive a threaded proximal member (catheter) 110 intothe lumen of the stent member 120. The female threaded coupling region1420 of the stent member 120 may receive a proximal member 110 which hasa male type thread arrangement 1410 over its outer surface within itscoupling region 150. This permits proximal member 110 to be coupled todistal member 120 by threading into position and later proximal member110 may be removed by unthreading (rotating) the proximal portion 110 ofthe device 100.

FIGS. 15A-15C depict the strand material used to close the proximal loop120 a of the distal portion (stent) 120 of the device 100 once it iswithin the renal pelvis of the kidney. This strand of material referredto as the proximal suture loop 1501 may pass through holes locatedthrough the sidewall of the bottom of the loop 120 a. As the distalstent loop or curl 120 a and the proximal stent loop or curl 120 b arestraightened for delivery, the distal curl 120 b of the stent member 120may reform upon straightener removal due to the large space in thebladder. The proximal loop 120 a may need mechanical encouragement toreform in the tighter renal pelvis region. The present device 100 canuse a proximal loop suture 1501 which is pulled in tension at theproximal hub 100 a of the device 100 to reform the proximal loop 120 aof the stent 120. This proximal loop suture 1501 may be removed bycutting one end of the strand at the hub 100 a and pulling on the otherend until it is fully removed. The proximal suture loop 120 b and itsfunction may act independently of the coupling mechanism.

FIGS. 16A, 16B, and 16C display several configurations of proximal hubs.The coupling components may extend out from various hub configurationsenabling removal and/or features such as a push button may permitdecoupling of the device. That is, the pull wire(s) or suture loop(s)may be retracted from various ports of the proximal hubs. FIG. 16A showsa proximal hub 100 a′ with a main port 101 a and a lateral port 101 b.In an example, the suture loop 1501 may be proximally retracted from thelateral port 101 b to facilitate the (re)formation of the proximal loop120 a and the pull wire 140 may be retracted from the main port 101 a torelease the stent member 120. FIG. 16B shows a proximal hub 100 a″ witha main port 101 a and two lateral ports 101 b, 101 c. The additionallateral port 101 c may, for example, be used for retraction of thesuture 130 after the pull wire 140 has been retracted. FIG. 16C shows aproximal hub 100 a″' with only a main port, which may be used for one ormore of the pull wire(s) or suture(s). When the stent member 120 hasbeen left implanted in the patient, the suture(s) may be one or more ofcut, retracted, or left in place.

Further nephroureteral stent systems and joining or coupling mechanismsare described below. Many of the elements of the figures and theircorresponding reference numbers are listed below.

1: Stent

2: Detachable drainage/delivery catheter

3: Hub

4: Loop suture lock

5: Loop suture

-   -   5 a: Tensioning end of loop suture    -   5 b: Loop locking end of loop suture    -   5 c: Removal end w/tab (for lock suture proximal exit hole 20)

6: Proximal loop

7: Distal loop

8: Distal radiopaque marker

9: Proximal radiopaque marker

10: Junction stent to drainage catheter (shown with gap for clarity)

11: Lock Suture

-   -   11 a: Distal lock suture loop    -   11 b: Hub attachment (example of possible location)    -   11 c: Distal lock suture tie down

12: Coupler, retractable

13: Protective cap (pull wire)

14: Protective cap (for loop suture 5)

15: Lure thread connector (standard)

16: Tapered tip

-   -   16 a: Drainage hole    -   16 b: Drainage hole

17: Drainage holes (interior of loops)

18: Lock/Release wire

-   -   18 a: Proximal part (going from coupler 12 to pull tab 19)    -   18 b: Distal end (going through lock distal lock suture loop 11        a)

19: Lock/Release wire pull tab

20: Lock suture proximal exit hole

21: Lock Suture Distal entry hole

22: Distal reinforcement on stent (e.g., SS hypotube)

23: Proximal reinforcement on catheter (e.g., SS hypotube)

24: Alternative reinforcement or in combination with otherreinforcement, higher durometer or tougher tubing than main body

25: Advancement Stop

26: Lock suture tie down reinforcement (swaged hypotube, for example,not shown swaged flush for clarity)

27: Separate lock/release wire

28: Inner member

29: Fixed coupler

30: Coupler to catheter attachment

31: Slip fit

32: Lock wire

33: Wire

As shown in FIGS. 17A-17F, a nephroureteral stent system 200 maycomprise three major components: a distal and releasable stent or stentmember 1, a catheter 2 and a hub 3, and a coupling and release mechanismwhich may comprise a loop suture 5, a lock suture 11, a retractablecoupler 12, a lock/release wire 18, and a lock/release wire pull tab 19.The hub 3 may be fixed to the catheter 2, while the stent 1 may bereleasably fixed to the catheter 2 at the junction 10 by the couplingand release mechanism. The coupling and release mechanism may operate ina manner similar to the coupling mechanisms described above and herein.For example, referring to FIG. 17C, the lock/release wire 18 maythreaded through the distal lock suture hub attachment 11 b of the locksuture 11, the lock/release wire may be retracted therefrom to releasethe lock suture 11 such that the stent 1 may decouple from the catheter2, and the lock suture 11 may be proximally retracted further.

A straightener (e.g., a hypotube with a hub) can be put in to straightenthe loops 6, 7 of the stent 1 out and the system 200 can be put over aguidewire in the body to be placed. The straightener can be then removedallowing the proximal and distal loops 6, 7 of the stent 1 to form.Usually, the proximal loop 6 will not form on its own in tight spacesand may need to be formed by pulling on the loop suture 5 similarlydescribed above with reference to FIGS. 15 a-15 c.

As shown in FIGS. 17A-17F, one end of the loop suture 5 c may be tieddown to a pull tab 20, the loop suture going down the inner lumens ofthe catheter 2 and of the stent 1 to the proximal loop 6 where it mayexit one drain hole 16 a and re-enters another drain hole 16 b andreturns to the hub through the loop suture lock 4. The two drainageholes 16 a, 16 b may be configured so that when the loop suture 5 istensioned, such as by pulling on tensioning end 5 a, the loops suture 5pulls the proximal loop 6 into a loop. The loop suture 5 can be lockedin place by lock mechanism 4 to help retain the system 200 in the body.Additional drainage holes may exist on the proximal loop 6, generallyresiding on the inner portion of the loop 6.

In some embodiments, the nephroureteral systems may not need the loopsuture 5 removed. In such systems, the loop suture lock 4 can beunlocked to free up the proximal loop 6 and the whole catheter 2including the loop suture mechanism can be removed. Such systems may notrequire the distal lock suture tie down 5 c and the lock suture proximalexit home 20; and instead, the ends of the loop suture 5 may beun-accessibly tied down in the hub 3. Nevertheless, it can be criticalto be able to withdrawal the loop suture 5 entirely before convertingand releasing the stent 1. Hence, the distal lock suture tie down 5 cand the lock suture proximal exit home 20 can be accessible.

The tension in the loop suture 5 can be relieved by unlocking the loopsuture lock 4, which can allow the proximal loop 6 to relax and un-foldas the system 200 is removed through an access channel/hole.

Referring to FIGS. 18A-18C, the coupling or lock mechanism for thesystem 200 can be similar to those described above and herein. The lockmechanism may comprise a lock wire (pull wire) 18 that may bepermanently affixed to a coupler (e.g., a coupling cylinder) 12 of theinner member and may pass beyond the coupling cylinder 12 to engage orthread through the lock suture 11 at the distal lock suture tie down 11c as shown in FIG. 18A. As shown in FIG. 18B, the lock wire 18 may beretracted to free the distal lock suture tie down 11 c. Such retractionfrees the lock suture 11 and can retract the coupler 12 from the stent1, allowing the lock suture 11 to be retracted and the stent 1 to bereleased.

In some embodiments, a coupler cylinder 29 may be affixed to thecatheter 2 through the coupler to catheter attachment 30 and may not beable to be independently pulled back (FIG. 19). A lock wire 32retractable to free the lock suture 11 may be separate from the coupler29. In some cases, however, the fixed coupler 29 may hang up on insidethe stent 1 during removal (for example, due to friction, biofouling,etc.) if not pulled back independently.

In some embodiments, the coupler 12 may be connected to a wire 33 thatis separate from the lock/release wire 27, and the wire 33 may be pulledas an additional step (which could be mitigated by interlocking thepullback actions).

In some embodiments, the coupler 12 may be attached to a co-axial innermember 28, which may be affixed to the hub so that it can be pull back.The coupler 12 may comprise an inner member, which may be solid polymer,nitinol, braided or coiled shafts (not shown).

Referring back to FIGS. 17A-17F, to deploy the stent portion 1, theoperator may first unlock the loop suture 11, remove the loop suture cap14, and pull the loop suture out. To actually deploy the stent 1, thecap 13 may be removed and the lock wire 18 may be pulled back by pullingthe lock wire tab. The lock wire 18 may be in communication (e.g.,attached) to the coupler 12 such that the coupler 12 may be pulled backwhile it is pulling out of the lock suture loop 11 b, disconnecting thestent 1.

As shown in FIG. 17C, an exemplary method of fixing the lock suture 11is for one end 11 c to be fixed near the distal end of the catheter 2and the other end 11 b fixed to the hub 3 for tensioning the catheter 2and stent 1 together after the lock wire 18 is in place. Fixing one end11 c near the distal end of the catheter 2 while having the other end 11b be fixed more proximally can reduce instances of the catheter materialpulling back or bunching up (and gaping at the junction) as the system200 is advanced. Alternatively, both ends of the lock suture 11 can betied down at the distal end or fixed down at the hub 3. The lock sutureends may be locked down or fixed by tying around two holes, gluing,embedding, swaging marker, etc.

The lock suture 11 may be made of a high tensile strength, lowelongation material and flexible material like UHMWPE (Spectra,Honeywell) or other material, including stainless steel or othermetallic materials, or a combination of materials. It could be a singleribbon with a hole at the end to pass lock wire through, or otherconfigurations.

The stiff coupler 12 may be made of implant grade materials such asstainless steel, NiTi, PEEK, or other materials know in the art. Moreflexible couplers are possible, but do not support the catheter 2 andstent 1 at the junction under bending, resulting in splaying open of thejunction.

Various configurations of hubs are also disclosed, including a triplearm hub 220 which may be preferred in at least some cases (FIGS. 22A,22B). A single side arm 221 of the triple arm hub 220 may comprise twopull tabs 222 a, 22 b. The hubs can be in axial configurations with pulltabs or laid out in a side arm or triple arm configuration.Alternatively, the hubs 230 could be axially stacked components (likerocket stages), that separate (unscrew for instance) in sequence toprovide the necessary actions (FIGS. 23A, 23B, 23C). As shown in FIGS.23B and 23C, the body of the hub 230 may be axially pulled apart so thatpull tabs 232 a, 232 b may be accessed. A handle with a slide or twistmechanism may be used in some embodiments. The hubs shown may use arotating hemostat type valve (shown in FIG. 25A by locks 250, forexample) to wrap and lock the loop suture, although other mechanismssuch as a center lever to lock the suture and seal out the side (shownin FIG. 25B, by lever mechanism 251, for example) may be used as well.

FIG. 24 shows further hubs that may be used for the devices 200, includea side armed hub 241, a barrel hub 242, and a triple armed hub 243.

In the side or triple arm hubs described above, the wire or suturescould be affixed directly to the caps, but may twist and bind if notprovided a anti twist feature in cap. Since ports 15 on these devices200 may need to be flushed periodically, a person un-familiar with thedevices 200 might unscrew a cap inadvertently. Hence in preferredembodiments, pull tabs are separate from caps.

In some embodiments, the catheter 2 and the stent 1 may be decoupledfrom one another electrolytically or by electrical resistance basedmelting of a connector. The device 200 may comprise a sacrificial jointbetween the catheter 2 and the stent 1 that may dissolve in the presenceof urine when an electrical charge is applied, similar to the mechanismsdescribed in U.S. Pat. Nos. 5,122,136 and 5,643,254. The device 200 mayuse current resistance to soften or melt a connector, and since theconnector may be internal to the catheter, no tissue may be affected bythe temperature and the volume of body fluids flowing through thecatheter may keep fluid temperatures within acceptable ranges. Thedevice 200 may comprise shape memory component(s) and heating thesecomponents by electrical current can cause them change shape to releasethe catheter 2 and stent 1 from one another.

As shown in FIG. 26, the lock suture 11 may be tied down to the catheter2 at multiple distal lock suture tie down locations 11 c. The catheter 2may be reinforced at the tie down locations 11 c with reinforcements 24.The reinforcements 24 may comprise coil reinforced areas. These coilreinforced areas may be provided so that the lock suture 11 does nottear through the material of the catheter 2 under high load scenarios,as discussed further below. In some embodiments, a coil or other mode ofreinforcement would also be located in a region of the lock suturedistal entry hole 21 of the stent 1.

Lock Suture Distal Termination Methods: At least one or both ends of thelock suture 11 may be terminated toward the distal end of the catheter 2to prevent separation of the stent-catheter junction under loadingscenarios during delivery of the device.

The suture 11 may be terminated on pull wire 18 by passing through thebraid of the suture 11 itself or tie knot to pull wire shaft. The knotor braid may slide longitudinally over the wire 18 as it is displaced orremoved during a detachment event.

The knotted suture 11 may terminate within the lumen of the catheter 2which may leverage against a small diameter hole. The hole which sutureknot leverages against may be covered with an adhesive, marker band,and/or other polymeric sheathing.

A hypotube or marker band may be applied or crimped to the outerdiameter, inner diameter, or embedded within the surface of the catheter2 and/or stent 1 polymer. The metallic surfaces of the applied hypotubeor marker band may be utilized for attaching suture material.

Lock Suture Hole Reinforcement: The holes punched (e.g., punched using acoring tool) through the wall of the catheter 2 and stent 1 in which thelock suture 11 passes through may require reinforcement to enhance thetear resistance of the thermoplastic used in many device applicationswhich may cause the catheter 2 and/or stent 1 to soften at bodytemperature for optimal patient comfort. Locking suture materials usablein some applications may have the propensity to tear through the holesin the wall of the device under high load scenarios. A stiff metallic,polymeric, or fibrous braid or coil may be embedded, extruded, orlaminated within the wall of one or more of the stent 1 or the catheter2 to prevent such tearing. A segment of hypotube or other high strengthmaterial may be embedded, overlaid, or affixed near the holes ofinterest, but typically only near that region so as to not greatlyimpact the overall comfort characteristics of the device, so the suturemay leverage against this stiff substrate under load.

While the convertible catheter devices are described above as being usedto deliver a nephroureteral stent, the convertible catheter devices andtheir methods of use may be applicable for other anatomical structuresas well. The dimensions and/or material properties of the convertiblecatheter devices may be modified to be appropriate for the otheranatomical structures. For example, convertible catheter devicesaccording to many embodiments may be suitable for use as a biliary stentto maintain the patency of a bile duct; and, the convertible catheterdevice usable to deliver a biliary stent may have a smaller proximalloop or a J-hook configuration of the proximal hook suitable for theshape of the gallbladder and/or gallbladder neck. In another example,convertible catheter devices according to many embodiments may besuitable for use as an ileal conduit catheter. While the convertiblecatheter devices adapted for use as a nephroureteral stent may have aproximal to distal loop distance ranging from about 20 cm to about 28cm, the convertible catheter devices adapted for use as ileal conduitcatheters would have a longer loop to loop distance.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A stent delivery system comprising: a catheterbody having an inner lumen and a proximal end and a distal end; a stentmember having an inner lumen and a proximal end releasably coupled withthe distal end of the catheter body; an inner member assembly disposedin the inner lumen of the catheter body and extending into the innerlumen of the stent member to concentrically align the catheter body andthe stent member; and a tether extending through or along the catheterbody and into the inner lumen of the stent member to form a loop over atleast a portion of the inner member assembly thereby securing the stentmember to the catheter body, wherein retraction of the inner member fromthe inner lumen of the stent member frees the inner member assembly fromthe loop such that the stent member is released from the stent body. 2.The stent delivery system of claim 1, wherein the inner member assemblycomprises a locking pull wire, the locking pull wire being threadablethrough the loop of the tether.
 3. The stent delivery system of claim 1,wherein the inner member assembly comprises a hypotube.
 4. The stentdelivery system of claim 1, wherein the inner member assembly isconfigured to be actuated with one or more pull tabs or rotatable capsat a hub coupled to the proximal end of the catheter body.
 5. The stentdelivery system of claim 1, wherein the tether extends through the innerlumen of the catheter body.
 6. The stent delivery system of claim 5,wherein the tether extends out of a lateral port of the catheter bodynear the distal end of the catheter body.
 7. The stent delivery systemof claim 5, wherein the loop formed by the tether extends into stentmember through a lateral port of the stent member to be threaded throughby the at least a portion of the inner member assembly within the innerlumen of the stent member.
 8. The stent delivery system of claim 1,wherein the tether has a fixed end near the distal end of the catheterbody and a free end, the tether extending proximally toward the free endand the proximal end of the catheter body.
 9. The stent delivery systemof claim 1, wherein the tether has a first end and a second end, thetether extending proximally toward both the first and second ends andthe proximal end of the catheter body.
 10. The stent delivery system ofclaim 1, wherein the stent member comprises a proximal loop and a distalloop.
 11. The stent delivery system of claim 10, wherein one or more ofthe proximal loop or the distal loop of the stent member have astraightened configuration and a looped configuration.
 12. The stentdelivery system of claim 11, wherein the one or more of the proximalloop or the distal loop is biased to assume the looped configuration.13. The stent delivery system of claim 11, further comprising a looppull wire extending through the inner lumen of the catheter body andcoupled to the proximal loop, wherein retracting the loop pull wirepulls the proximal loop into the loop configuration or lowers a radiusof the proximal loop.
 14. The stent delivery system of claim 13, whereinthe loop pull wire extends out from a first lateral port of the stentmember near the proximal end of the stent member and extends back into asecond lateral port of the stent member near a distal end of theproximal loop.
 15. The stent delivery system of claim 13, wherein theloop pull wire is retractable from a pull tab or rotatable cap at a hubcoupled to the proximal end of the catheter body.
 16. A method ofdelivering a nephroureteral stent, the method comprising: advancing astent delivery system through a percutaneous access site so that adistal end of a stent member of the stent delivery system is positionedin a bladder and a proximal end of the stent member is positioned in arenal pelvis, wherein the distal end of the stent member forms a distalloop in the bladder; actuating the proximal end of stent member to forma proximal loop in the renal pelvis; decoupling the stent member from acatheter body of the stent delivery system; and retracting the catheterbody of the stent delivery system from the percutaneous access site,leaving the stent member in place.
 17. The method of claim 16, whereinactuating the proximal end of the stent member to form a proximal loopin the renal pelvis comprises retracting a loop pull wire extendingthrough the catheter body to reduce a radius of the proximal end of thestent member.
 18. The method of claim 16, wherein decoupling the stentmember from the catheter body comprises retracting a lock pull wire fromthe stent member to free a tether loop extending into the stent memberfrom the catheter body.
 19. The method of claim 16, wherein decouplingthe stent member from the catheter body comprises retracting an innermember from the stent member, the inner member being configured toconcentrically align the catheter body with the stent member whenadvanced therethrough.
 20. The method of claim 16, further comprisingleaving the stent member and the catheter body of the stent deliverysystem in place for at least 3 days before decoupling the stent memberfrom the catheter body and retracting the catheter body from thepercutaneous access site.
 21. The method of claim 20, further comprisingdraining urine through the catheter body of the stent left in place forthe at least 3 days.
 22. The method of claim 20, further comprisingcapping the catheter body of the stent left in place for the at least 3days.